POP LOOP - Endlessly Popping Popcorn Bucket Fidget (Cam Mechanism, No Supports)

A striped popcorn bucket with a secret: a clicky thumbwheel under the bottom. Roll it, and five chunky kernels burst up out of the heap in a little rhythm, pop... pop-pop... POP!... pop, then settle back down. It never runs out of popcorn.

HOW IT WORKS

• The thumbwheel is a face cam: five ramps, one on each concentric track

• Each kernel sits on a square stem that rides its own track. A ramp lifts the stem 4-10 mm, then it slides back down by gravity

• The ramps sit at different angles, so the kernels pop at different moments. The biggest kernel does the big POP

• All ramps are 40 degrees or less, so the wheel works in both directions, with 24 clicks per turn

• Square stems stop the kernels spinning, and a collar under the guide deck keeps them captive: you can't pull a kernel off

DETAILS

• Size: 69 mm diameter x 95 mm tall

• 16 printed parts, about 5 minutes to assemble

• Removable twist-lock bucket sleeve

• No supports, glue, screws, springs or magnets

PRINT SETTINGS

• The 3MF is ready to print with 4 plates: 0.2 mm layers, 0.4 mm nozzle, 3 walls, 15% gyroid infill, no supports

• Kernels and stems: 0.12 mm layers; stems and the detent tab: 100% infill (already set in the 3MF). The popcorn heap has a brim (its tube end is small)

• Plates by colour: AMS striped sleeve (red + white) and base (red); cam wheel, guide deck and detent tab (white); popcorn heap, kernels and stems (cream or butter yellow - swap filament)

• Print EITHER the AMS sleeve (real red and white stripes) OR the optional single-colour sleeve on the last plate (raised stripes)

• Every part is already oriented. All overhangs are 45 degrees or less, or short bridges. Fits a 180 x 180 mm bed

ASSEMBLY

1. Drop the detent tab into the pocket in the base foot, bump up, with the pad toward the outside edge.

2. Slide the cam wheel onto the column, ramps up, and give it a spin. It should click.

3. Push each stem up through its square hole in the guide deck from underneath, so the collar ends up below the deck. Match the notches on the stem to the dimples beside each hole (from the middle outward: k4, k2, k1, k3, k5).

4. Holding the stems, lower the deck onto the column (the D-shaped key only fits one way) until it sits on the shoulder.

5. Lower the popcorn heap over the column, threading the five stems through its square holes.

6. Press each kernel onto the top of its stem, matching the files k1-k5 to the stem notches.

7. Slide the striped sleeve up from below over the wheel, line up the three slots with the deck pins, push up and twist about 16 degrees until it snaps and locks.

TIPS

• Smoothest action: lightly sand the cam ramp tops and run the stems through their holes a few times before assembly

• Kernel too tight on its stem? Sand the stem tip lightly. Loose? Add one wrap of paper

• If a kernel sticks up, check that its stem is in the right hole (count the notches)

• To take it apart, twist the sleeve back and slide it down

Original design by Kirimas Studio.